The applicant of the present invention proposed a sole structure for a sport shoe such as shown in Japanese Patent No. 3215664. In the sole structure shown in the patent publication, the wavy corrugated sheet is interposed inside the midsole of a soft elastic member and it extends from the heel part of the midsole through the midfoot part to the position near the thenar eminence of the forefoot part. Thereby, a lateral swing can be prevented at the region from the heel part to the midfoot part of the midsole after impacting the ground, thus securing stability during running (see para. [0091] and FIGS. 5-7).
In the structure described in the above publication, the wavy corrugated sheet, which is disposed at the region extending from the midfoot part of the midsole to the position near the thenar eminence of the forefoot part, enabled an increase of resiliency to some degree when impacting the ground on the forefoot part during activities, but it was not sufficient. For example, in indoor sports such as volleyball, handball or the like, the prior-art structure did not adequately correspond to demand that accelerating force is further increased during activities and quicker movements are achieved.
The present invention has been made in view of these circumstances and its object is to provide a sole structure for a sport shoe that can increase accelerating force during activities and achieve quick movements.